NH Snow Cover Extent

The Northern Hemisphere snow cover extent during March 2012 was near average and ranked as the 23rd largest (24th smallest) March snow cover extent in the 46-year period of record. The monthly snow cover extent was 6,000 square km (2,320 square miles) above the long-term average of 40.4 million square km (15.6 million square miles). This is the smallest March snow cover extent for the Northern Hemisphere since 2009. There was considerable variability between the Eurasian land area and the North American land area snow cover during the month.

During March 2012, the North American snow cover extent was much below average, ranking as the fourth smallest March snow extent on record for the continent. Much warmer than average conditions across the eastern U.S. and southern Canada limited snow cover for the month there, while above-average snow fell across the western portions of the U.S and Canada. The monthly snow cover extent was 14.6 million square km (5.6 million square miles), which is 1.1 million square km (425,000 square miles) below average. This marked the smallest March snow cover extent for North America since 2000.

Eurasian snow cover extent during March was 25.6 million square km (9.9 million square miles), which is 1.1 million square km (425,000 square miles) above average. The March snow cover extent for the continent was the ninth largest on record. This was the largest Eurasian snow cover extent for March since 1987. During the month, below-average snow cover was observed across central Europe, Mongolia, and parts of western China. Above-average snow cover was observed across western Russia, much of Turkey, and central and eastern China.

Sea Ice Extent

According to the National Snow and Ice Data Center (NSIDC), the Northern Hemisphere sea ice extent — which is measured from passive microwave instruments onboard NOAA satellites — averaged for March 2012 was 15.21 million square kilometers (5.87 million square miles), 3.42 percent below the 1979-2000 long-term average, and the ninth smallest March ice extent on record. This is the largest March Arctic sea ice extent since 2008, and one of the largest of the last decade. March 2012 is the 19th consecutive March and the 130th consecutive month with below-average Arctic sea ice extent. March Arctic sea ice extent has decreased at an average rate of 2.6 percent per decade.

According to the analysis by the NSIDC, Arctic ice cover remained above average in the Bering Sea, similar to the rest of the winter season. Ice extent was also above average in Baffin Bay, between Greenland and Canada, and the Sea of Okhotsk. In the Kara Sea, where ice extent had been below average during January and February, ice rebounded to near-average levels during March. Ice extent in the Barents Sea remained well below average.

Arctic sea ice reached its annual maximum extent on March 18th, which is 12 days later than the average date for the annual maximum. The annual melt cycle began after the maximum extent occurred and the footprint of Arctic sea ice will continue to shrink until it reaches its annual minimum extent which typically occurs in September.

The March 2012 Southern Hemisphere sea ice extent was 5.0 million square km (1.9 million square miles), 16.0 percent above the long-term average — the fourth largest March extent on record. This is the largest March sea ice extent for the Southern Hemisphere since 2008. Throughout the month, Antarctic sea ice trended above average. Southern Hemisphere March sea ice extent has increased at an average rate of 3.2 percent per decade with significant inter-annual variability.

For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page.

Citing This Report

NOAA National Centers for Environmental Information, State of the Climate: Global Snow and Ice for March 2012, published online April 2012, retrieved on December 9, 2016 from http://www.ncdc.noaa.gov/sotc/global-snow/201203.